Instructions

1. Season the oxtails all over with 1 tablespoon salt and let sit at room temperature for 2 hours.
2. In a small frying pan over medium heat, combine all the peppercorns and the star anise and toast, tossing or stirring frequently, until fragrant, about 2 minutes. Immediately transfer to a plate and let cool. Make a sachet of the spices and bay leaves by wrapping in a double layer of cheesecloth and tying closed with kitchen twine. Add the ginger to the same pan over medium-high heat and char until blackened in spots, 3 to 4 minutes per side.
3. Fill a 10-quart or larger pot halfway with heavily salted water (it should remind you of seawater) and bring to a vigorous boil over high heat. Add the oxtails and blanch for 1 minute, then transfer them to a colander and rinse under cold water. Discard the blanching water and rinse out the pot.
4. Return the oxtails to the pot. Add the sachet, ginger, and chicken stock and bring to a simmer over high heat. Turn the heat to medium-low and very gently simmer, uncovered and skimming every hour or as needed, until the oxtails are tender but not falling off the bone, about 4 hours. About an hour before the oxtails are done, taste the broth and season with salt.
5. Preheat the oven to 425ºF. Place the daikon, carrots, and mushrooms on a rimmed baking sheet, drizzle with the neutral oil, and toss to combine. Roast until they start to brown on the bottom, about 20 minutes, then remove from the oven and let cool. Transfer to an airtight container and store in the refrigerator for up to 1 day.
6. Transfer the oxtails to a large bowl. Line a colander with a double layer of cheesecloth and fit over a 5-quart pot. Strain the broth and discard the solids.
7. If serving the same day, skim the fat from the surface of the broth. If serving the next day, return the oxtails to the broth. Let cool, then cover and refrigerate. When ready to finish the soup, skim the hardened fat from the surface of the broth. Warm over medium heat until the broth liquefies, then transfer the oxtails to a large bowl.
8. Bring the broth back to a simmer. Add the roasted vegetables and continue to simmer, uncovered, until just knife-tender, about 15 minutes. Return the oxtails to the broth and simmer until they are warmed through, about 5 minutes more. Taste the broth and season with salt.
9. Serve the soup hot, garnished with the dressed watercress.
10. Fill a 12-quart or larger pot halfway with tap water and bring to a vigorous boil over high heat. Add the chicken bones and blanch for 10 to 15 seconds, then transfer to a colander set in the sink. Discard the cooking water and wash out the pot.
11. Add the chicken bones, onion, celery, carrot, thyme, savory, and 5 quarts cold water to the pot and bring to a hard simmer over high heat. Skim off as much scum as possible from the surface. Turn the heat to medium-low and simmer gently for about 4 hours, skimming every hour or as needed.
12. Line a fine-mesh strainer or colander with a double layer of cheesecloth (or a coffee filter) and fit it over a large bowl. Strain the stock, discard the solids, and let cool.
13. Transfer the stock to an airtight container and store in the refrigerator for up to 5 days, or in the freezer for up to 2 months. When ready to use, warm to a gentle simmer over medium heat.